Road safety campaigners say the problem of unfit drivers is growing because of an ageing population Photograph: Christopher Furlong/Getty Images

Road safety campaigners have accused the Department for Transport of burying the findings of a research project that suggested thousands of drivers are unfit to be on the road because of failing health and disability.

The study found that doctors, nurses and other health professionals are failing to stop people driving when they are a danger to themselves and other road users. The problem is growing because of the ageing population.

Researchers discovered that only one in four motorists with a condition that could affect their fitness to drive had received correct advice from a health worker. Among drivers with diabetes, which can affect vision and leg movement, fewer than one in 30 had received any advice.

The study, which called for better training of health workers, regular eye tests for all drivers and restricted driving licences for certain medical conditions, was submitted in 2008 but withheld by the transport department for two years before being put on its website with no official publicity. A spokeswoman for the department said there were "no plans" to change the existing eye test for drivers or current licence arrangements.

Motorists are required to notify the Driver and Vehicle Licensing Agency of any medical condition that could affect their ability to drive safely. Health workers are expected to advise their patients on such conditions and, if necessary, to notify the DVLA in confidence if a patient is ignoring advice to stop driving.

After the age of 70, drivers must renew their licence every three years on the basis of a self-completed questionnaire. There are currently almost 14,500 holders of full licences who are aged 80 or older, including 133 aged 100 or more.

The research project was commissioned by the transport department from a team at Warwick University. The team surveyed medical schools, health workers and drivers with medical conditions and used a range of research techniques including deployment of an actor pretending to be unfit to drive. Only one in five health professionals gave the actor any advice on driving.

Researchers found 69 of the 140 drivers surveyed should have been advised to stop driving for at least a period of time, but only 23 had received such advice. Carol Hawley, a psychologist who led the research team, said there was confusion among health workers over who was responsible for telling drivers they should stay off the road after an episode such as a stroke, an operation or a bout of severe depression.

"The typical response we found was, 'Yes, we know it's important, we know somebody should be doing it, but we don't think it should be us'."

She added that leaving the onus on motorists to own up to a serious condition, and turn themselves in to the DVLA, was a recipe for inaction. "It's like turkeys and Christmas: if you are going to lose your licence, you aren't going to do it, are you?" Hawley said.

Roadpeace, a charity that campaigns on behalf of road crash victims, said the research should have been a wake-up call for the DVLA and the medical profession in particular. It had confirmed the charity's view that much more needed to be done to keep unfit drivers off the road. "With our ageing population and increase in diabetes, this problem can be expected to worsen," Amy Aeron-Thomas, Roadpeace's executive director, said. "We call on the government to remember that impairment is not restricted to drink or drugs."

The transport department denied suppressing the report. Its spokeswoman said some of the 15 key recommendations had been acted upon as part of a continuing dialogue between the DVLA and leaders of the health professions.

A DVLA spokesperson said: "We have taken steps to address the issues set out in this report to ensure that those working in the health services have the tools they need to provide clear advice on fitness to drive.

"DVLA has worked closely with he General Medical Council to provide medical advice on fitness to drive and has produced a medical A-Z which is available on Direct.gov to help motorists understand whether they need to notify DVLA about a medical condition.

"We are also working with interested bodies to develop a learning module on medical conditions and driver licensing awareness to better train healthcare professionals."

CASE STUDY

Natalie Wade was shopping for her wedding dress when she was knocked down on a pelican crossing by driver who had gone through a red light. She died five days later, on Valentine's day 2006, with her fiancé at her bedside.

The 78-year-old motorist was found to be blind in one eye with limited sight in the other. He was charged with causing death by dangerous driving, but died before the case could reach court.

For the Rev Brenda Gutberlet, Natalie's aunt, the tragedy proved a painful insight into the haphazard working of the fitness-to-drive system. It emerged that the driver, who had renewed his licence three times after passing 70, had been consulting two doctors about his sight, but neither had contacted the DVLA about his continued driving.

"The honesty-based system was really found wanting," said Gutberlet, a Methodist minister in Rochford, Essex, where her niece was killed.

"After the publicity about the case, we were bombarded with letters from people saying: 'My uncle Billy or my aunt Flossy should not be on he road. How can we get them taken off?'

"The truth is, politicians don't want to know [about reforming the system]. The motoring lobby is so powerful and the 'grey' vote is so important now. But above the age of 50, your sensory loss increases naturally. It's not ageist to say you need to be checked."